Object - JavaScript - MDN Web Docs

All objects in JavaScript are descended from Object ; all objects inherit methods and properties from Object.prototype , although they may ... SkiptomaincontentSkiptosearchSkiptoselectlanguage給開發者的網頁技術文件JavaScriptJavaScript參考文件標準內建物件ObjectArticleActions正體中文(繁體)ThispagewastranslatedfromEnglishbythecommunity.LearnmoreandjointheMDNWebDocscommunity.語法描述Object建構式屬性Object建構式方法Object物件實體與Object原型物件範例規範瀏覽器相容性參見RelatedTopicsStandardbuilt-inobjectsObjectPropertiesObject.prototype.constructor(en-US) 已棄用 Object.prototype.__proto__Methods 已棄用 Object.prototype.__defineGetter__()(en-US) 已棄用 Object.prototype.__defineSetter__()(en-US) 已棄用 Object.prototype.__lookupGetter__()(en-US) 已棄用 Object.prototype.__lookupSetter__()(en-US)Object.assign()Object.create()Object.defineProperties()Object.defineProperty()Object.entries()(en-US)Object.freeze()Object.fromEntries()(en-US)Object.getOwnPropertyDescriptor()(en-US)Object.getOwnPropertyDescriptors()(en-US)Object.getOwnPropertyNames()(en-US)Object.getOwnPropertySymbols()(en-US)Object.getPrototypeOf()Object.hasOwn()(en-US)Object.prototype.hasOwnProperty()Object.is()(en-US)Object.isExtensible()(en-US)Object.isFrozen()(en-US)Object.prototype.isPrototypeOf()(en-US)Object.isSealed()(en-US)Object.keys()Object.preventExtensions()Object.prototype.propertyIsEnumerable()(en-US)Object.seal()(en-US)Object.setPrototypeOf()(en-US)Object.prototype.toLocaleString()(en-US)Object.prototype.toString()(en-US)Object.prototype.valueOf()(en-US)Object.values()(en-US)語法描述Object建構式屬性Object建構式方法Object物件實體與Object原型物件範例規範瀏覽器相容性參見ObjectObject建構式可用於建立物件包裝（objectwrapper）。

語法//Objectinitialiserorliteral {[nameValuePair1[,nameValuePair2[,...nameValuePairN]]]} //Calledasaconstructor newObject([value]) 參數 nameValuePair1,nameValuePair2,...nameValuePairN Pairsofnames(strings)andvalues(anyvalue)wherethenameisseparatedfromthevaluebyacolon. value 任意值。

描述TheObjectconstructorcreatesanobjectwrapperforthegivenvalue.Ifthevalueisnullorundefined,itwillcreateandreturnanemptyobject,otherwise,itwillreturnanobjectofaTypethatcorrespondstothegivenvalue.Ifthevalueisanobjectalready,itwillreturnthevalue. Whencalledinanon-constructorcontext,ObjectbehavesidenticallytonewObject(). 也可以參考objectinitializer/literalsyntax.Object建構式屬性 Object.length Hasavalueof1. Object.prototype AllowstheadditionofpropertiestoallobjectsoftypeObject. Object建構式方法 Object.assign() Createsanewobjectbycopyingthevaluesofallenumerableownpropertiesfromoneormoresourceobjectstoatargetobject. Object.create() Createsanewobjectwiththespecifiedprototypeobjectandproperties. Object.defineProperty() Addsthenamedpropertydescribedbyagivendescriptortoanobject. Object.defineProperties() Addsthenamedpropertiesdescribedbythegivendescriptorstoanobject. Object.entries()(en-US) 實驗性質 Returnsanarrayofagivenobject'sownenumerableproperty[key,value]pairs. Object.freeze() Freezesanobject:othercodecan'tdeleteorchangeanyproperties. Object.getOwnPropertyDescriptor()(en-US) Returnsapropertydescriptorforanamedpropertyonanobject. Object.getOwnPropertyDescriptors()(en-US) Returnsanobjectcontainingallownpropertydescriptorsforanobject. Object.getOwnPropertyNames()(en-US) Returnsanarraycontainingthenamesofallofthegivenobject'sownenumerableandnon-enumerableproperties. Object.getOwnPropertySymbols()(en-US) Returnsanarrayofallsymbolpropertiesfounddirectlyuponagivenobject. Object.getPrototypeOf() Returnstheprototypeofthespecifiedobject. Object.is()(en-US) Comparesiftwovaluesaredistinguishable(ie.thesame) Object.isExtensible()(en-US) Determinesifextendingofanobjectisallowed. Object.isFrozen()(en-US) Determinesifanobjectwasfrozen. Object.isSealed()(en-US) Determinesifanobjectissealed. Object.keys() Returnsanarraycontainingthenamesofallofthegivenobject'sownenumerableproperties. Object.preventExtensions() Preventsanyextensionsofanobject. Object.seal()(en-US) Preventsothercodefromdeletingpropertiesofanobject. Object.setPrototypeOf()(en-US) Setstheprototype(i.e.,theinternal[[Prototype]]property) Object.values()(en-US) 實驗性質 Returnsanarrayofagivenobject'sownenumerablevalues. Object物件實體與Object原型物件AllobjectsinJavaScriptaredescendedfromObject;allobjectsinheritmethodsandpropertiesfromObject.prototype,althoughtheymaybeoverridden.Forexample,otherconstructors'prototypesoverridetheconstructorpropertyandprovidetheirowntoString()methods.ChangestotheObjectprototypeobjectarepropagatedtoallobjectsunlessthepropertiesandmethodssubjecttothosechangesareoverriddenfurtheralongtheprototypechain.屬性{{page('/zh-TW/docs/Web/JavaScript/Reference/Global_Objects/Object/prototype','屬性')}}方法{{page('/zh-TW/docs/Web/JavaScript/Reference/Global_Objects/Object/prototype','方法')}}範例UsingObjectgivenundefinedandnulltypes下面例子儲存一個空物件至變數o varo=newObject(); varo=newObject(undefined); varo=newObject(null); UsingObjecttocreateBooleanobjects下面例子儲存Boolean物件在o: //equivalenttoo=newBoolean(true); varo=newObject(true); //equivalenttoo=newBoolean(false); varo=newObject(Boolean()); 規範SpecificationECMAScriptLanguageSpecification#sec-object-objects瀏覽器相容性BCDtablesonlyloadinthebrowser參見 Objectinitializer Foundaproblemwiththispage?EditonGitHubSourceonGitHubReportaproblemwiththiscontentonGitHubWanttofixtheproblemyourself?SeeourContributionguide.Lastmodified:2022年9月20日,byMDNcontributors